I have to say it was much easier to watch than the previous two. I thought the credibility of the plot took a little bit of a hit. Remember in ROTJ when Luke asks Leia if she remembered her "real" mother? She said she remembered a little of her and how she was beautiful. How could she remeber her real mother if she died at childbirth. She had to be talking of Padme, because the Organas lived till they were blown up on Alderaan by the Death Star (per their biographies on the Star Wars playing cards my son has).
Also, Palpatine tells Vader that Vader killed Padme in his fit of rage. How does Palpatine ever explain the emergence of Luke later on? Vader never asks for an explanation of his lie.
Also at the end of ROTS, the Death Star is under construction. Now there is 20 years between ROTS and A New Hope when the Death Star goes operational. What the heck were Vader and the Emperor doing for 20 years? And after the Death Star was blown up, they were able to start on the second Death Star, which was double the size of the first one, and have it operational in just a few years.
Yeah, I'm being nitpicky. Overall, it was a good film, almost worthy of being in the league of the original trilogy.
I rewatched ROTJ Saturday for exactly your first point. Leia surprised me by stating that what she remembered of her mother was feelings. That she was kind and beautiful but sad, or something to that effect. So, again, maybe some Force mumbo-jumbo. Bah, this isn't Star Trek, we don't need airtight explanations =)
Number two:
Vader: My master, this "Luke Skywalker" from Tatooine. I have a feeling he is my son.
Palpatine: Huh. Maybe, I never really saw Padme's body, I just assumed she was dead. Then we got her obituary notice from the Theed Gazette and I figured I was right. O well, find your son and we will have a Teddybear picnic once he converts to the Dark Side.
Vader: Ok...
Number 3:
The Emporer was establishing the Moff and Grand Moffs (Imperial Governors) and undermining the power of the Senate. Vader was studying the Dark Side. The standard idea behind the Second Death Star (which was only about half done in ROTJ) is that the Emporer had already begun construction before the first was destroyed.
Again, explanations aren't necessary, but there are some ideas =)